Filtered electrical connectors are known. Conventional filtered electrical connectors use a ferrite bead or a coil, or both, for attenuating and filtering electrical signals directed through the electrical connector. Coils provide filtering functions which show very distinct peaks of attenuation at certain (resonance) frequencies while the filtering performance between the peaks is poor. Ferrite beads provide a more uniform attenuation over the frequency spectrum but still show better filtering performance in certain frequency ranges than in others.
A particularly important application for filtered electrical connectors are connectors for connecting vehicle control electronics with a squib or igniter of an air bag device. An electrical deployment signal is directed through the connector for actuating the air bag device. In absence of the deployment signal, it must be made sure that the air bag device in not inadvertently deployed by induced signals. Such signals may be induced, for example, by mobile telephones which transmit signals at particular frequencies such as 900 MHz, 1.8 or 1.9 GHz. Of course, in today's environment filled with electronics, signals at many different frequencies may be induced and might cause actuation of the air bag device.
Another important consideration are spatial constraints. Miniaturization is an important trend in industry, and it is particularly important for connectors for air bag devices which are built into various places in automobiles where there is little space available such as the steering wheel, seat portions, or structural portions of the vehicle.
It is thus an important object of the invention to overcome one or more of the problems associated with prior art filter assembly or filtered electrical connectors.
Another object of the invention is to improve the filtering performance of filtered electrical connectors without substantially adding to the size and cost of the connector.